CGI Programming

CGI stands for common gateway interface, and is a standardized method of controlling dynamic content and data on HTTP servers, and databases on those servers. CGI allows forms to be filled out on web pages and data to be entered and updated within a database. A database at its simplest is a machine that answers queries just as servers are machines that answer requests from web browsers. The information held within the form or query on average needs to be processed by an application; CGI can be any number of different programming languages or scripts. These languages supply a consistent method for these actions to be performed.

Essentially, CGI is the portal in which languages like Perl, C, C++ and Java can be used to execute actions and retrieve data. On the web, CGI applications allow the internet browser to communicate with the server, and send and receive data. The common gateway interface calls or tells the applications to execute and perform the designated or programmed request. In the case of a web browser, this means asking for the file located at the URL address in the browser. The CGI then executes the request and returns the file at that location to the browser. Since HTML files are static, they will have applications as part of their coding or mark up to allow for the use of applications for retrieving customer information, images, PDF files located on the server, or any other form of dynamic information for a web page.